Method of producing refractory fiber laminate



June 14, 1960 J. s. NACHTMAN 4 METHOD OF PRODUCING REFRACTORY FIBERLAMINATE Original Filed Feb. 25, 1953 3 Sheets-Sheet 1 EXHAUST GASESINVENTOR. I JOHN S. IVACHTMA/V A T TOR/YE Y5 June 14, 1960 J. s.NACHTMAN 2,940,886

METHOD OF PRODUCING REFRACTORY FIBER LAMINATE Original Filed Feb. 25,1953 3 Sheets-Sheet 2 EXHAUST GASES COATING UNIT COATING UNIT INVENTOR.JOHN S. NACH T MAN A T TORNE Y5 COATING UNIT June 14, 1960 J. 5.NACHTMAN METHOD OF PRODUCING REFRACTORY FIBER LAMINATE Criginal FiledFeb. 25,1955

3 Sheets-Sheet 3 CrzommaG 10 45b:

INVHVTOR.

JOHN S. NAGHTMA/V By W W ATTORNEYS DIETHOD OF PRODUCING REFRACTORY FIBERLAMINATE John S. Nachtman, 2801 Quebec St. NW.,

Washington, D.C.

Original application Feb. 25, 1953, Serial No. 338,923,

now Patent No. 2,699,415, dated Jan. 11, 1955. Divided and thisapplication Jan. 10, 1955, Ser. No.

8 (CL 154-91 (Granted under Title 35, US. Code (19 52), sec. 266) Theinvention described herein may be manufactured and used by or for theGovernment of the United States of America for governmental purposeswithout the payment of royalties thereon or therefor.

This invention relates to a new and improved method for continuouslyproducing coated refractory fibers which can be used to produce arefractory fiber laminate.

This application is a division of my copending application Serial Number338,923, filed February 25, 1953, now U.S. Patent No. 2,699,415.

At the present time many advancements in the use of atomic power andjet-propulsion units have been retarded or arrested because of the lackof suitable materials. It is well known that the efiiciency of ajet-propulsion unit could be materially increased provided a lightweightmaterial was available having high strength at temperatures between 500and 1200 F.. None of the known materials have the proper physicalcharacteristics to successfully withstand these conditions. r

I have? found anew and improved refractory fibrous material laminatewhich can withstand extreme high temperatures, for example between 500and 1200 F., and at the same time maintain high strengthcharacteristics. The refractory fibrous material may comprise eitherglass fibers, ceramic fibers or mineral fibers such as alumina fibers.

It is well" known that high tensile strength. The ultimate tensilestrength of glass fibers is known to exceed 300,000 pounds per-squareinch. Many attempts have been made to employ this high strengthcharacteristic of glass fibers by embedding them in resins to makevarious laminates. The resins, however, are by comparison weak andflexible. When a load is applied to a fibrous glass and resin laminate,the

glass fibers possess extremely An important object of the invention isto provide a method for the production of refractory fiber laminate withimproved physical characteristics, at high temperatures, far superior toany known fibrous laminate. V

A further object of the invention is to provide a novel method forcontinuously and uninterruptedly applying a "coating upon continuouslymoving refractory fibers as they emerge from a furnace'or other sourceof molten refractory material, and are in what may be considered as anascent state.

Another object of the invention is to provide a novel method foreffecting improved bonding between con tinuously moving refractoryfibers and diverse materials. Still a further object of the invention isto provide a novel method for embedding continuously moving refractoryfibers in a diverse material, or metal, to form a composite structurehaving the strength of the refractory fibers and properties of thediverse material or metal.

I have found that the above-mentioned objects and other desirableadvantages may be attained by the method of my invention whichcomprises, coating the continuous ly moving refractory fibers as theyleave the bushing in the refractory furnace, with at least one'metallicand/or inorganic coating, and then bonding the moving coated fiberstogether to form a laminate, by applying at least one bonding materialcomprising a metallic and/or organic, and/or inorganic bonding material.

It is apparent from the foregoing, that the process is of wideapplication and is susceptible of great variations. For example, thecoating material may be any desired metal or inorganic compound, orcombination of metals, inorganic compounds, andporganic compounds.

The following named metals and/or alloys thereof are examples of themetals that can be applied to the moving refractory fibers; alone or ina combination; titanium, copper, nickel, zinc,'chromium, iron, tin,molybdenum; zirconium, aluminum, lead, magnesium, 'et cetera. Inaddition to these metals, metallic oxide coatings can be formed, such asbydisassociation of metallo-oxychlorides,

O metallo-oxyhydrides and metal hydrides.

resin because of its low tensile strength, creeps or distorts slightly,While the glass being of high tensile strength, stays in place and takesthe load. In order for the glass fibers to take the load eficiently, thebond between the resin and the glass must be very strong. In practicethe bond between the glass fibers and the resin has been 5:)

found to fail because of slippage between the glass fibers and the resinafter the laminate has been exposed to the elements and to repeated use.One cause of this slippage is the poor adhesion or non-wetting effectbetween glass and resin. Many attempts have been made to correct thisfailure by forming a better bond between the glass fibers and thelaminating material. However, until my discovery, no satisfactory methodfor doing this was known to the art. I have found a new and improvedmethod for producing a glass-fiber laminate having thedesirablecharacteristic of being able to withstand high temperatureswhile being subjected to high strength demands.

' The principal object of'this invention is to provide a H Theaforementioned coatings can be applied by well known means, for example,by molten baths, inetallizing,

gas plating, vapor deposition, fused salts and/or electrolytes.

Inorganic compounds which can be applied alone or in combination, as acoating on the moving refractory fibers as they emerge from the bushingof the refractory furnace are as follows: borates, zirconates,metallo-fluoroborosilicates, titanates, metal phosphates, phosphates,metallooxychlorides, et cetera.

The inorganic coating can be applied by well known means, for example,by a spraying apparatus, by a clipping or molten bath apparatus, etcetera.

All of the aforementioned coatings, or combinations thereof, can beapplied on the continuously moving refractory fibers after they emergefrom the bushing in the refractory furnace, and are in what may beconsidered a nascent state.

It may be desirable in some instances to apply a con-' ductive coatingto the moving refractory fibers prior toing of the furnace. The gasescan be used whencertain Fatented June 14, 1960 i feceptiye condition forthe coa't ing.

V well 'lznown physical'properties' are desired and when the coatingapparatus'is locatedta distance away from the bushing. They may also beused when it is desirable to prevent exposure of the ,moving fibers, forany long period of time, toflan' atmosphere that may iniurio'u'slyiafieet the physical properties of the refractory'fibers.

'It is we'lljknown that when fibers are drawn from a 1 metal-bearing,molten glass mixture that ithe'lmetal ions tend, to migrate'to'thesurface of the nss' fibers'teirer 'a metallic film. Se'e 'fdr, examplel'he Electrical am Thomas DI Calli'nan, and Robert T. -Incas,.Nayal Research Laboratory, Washington, DC. When such'fjibers are cooled by.exposure to'the atmospherei the toox'idi ze and form' a' metallic oiide'coating.- Similar Phenomena bccur respect to chime mineral 1 fibers."Therefore, a second function f" the aforemenr a base 1 metal andtothereby a in a more honed gases to reduce such oxide films or coatingsto Theinert', reducing dAor on-oxidi zing gases must e fi e f m i' c d mu ties t r ent them and diagrammatic, t showing a e 4 e. Fig. 2 is avertical cross-sectional'view through an apparatus for producing 'a'1aaiiaateaerding tame teachings of this invention.

Fig 3 is a side view in elevation partially sectioned anddiagrammatic,shouting an electrostatic spray means I fer'coating t tr tscwry fibers L .t

Fig; 4 is-a side view 'n elevation partially r and diagrammatic,showingan electroplating means for coating h ef actor be s Fig. 5 s aside view. inelidtidn partially sectioned coating the refractoryfibersgFigi'disa' sidf :View. in e'ileva n, p 'all' ectioned andf diagrammatic,showing" a raiser deposit njm'eans for'coating therefra'etory fibers. Y

:Fig.- 7 is a perspective viewof-"the type ofcontact 1 rolls. useit n hest ne apra esiss :E sa 11' throu h V is a'plafimlm nglwhiehis moviedwith.

from attacking the refractory fibers. 'Ihey can be main tfainedatanyftemperaturedesired, depending on thefinal physical iproperti'es thatit is' desiredfto obtain in the tFor example, when applying a metalliccoating itmay be desirable to maintainthe temperature of the fibersatatemperat ire comparatively higher than when applyingfan inorganiccoating. w; The inorganic coatings may be applied relatively close'tothebushing, and'in this case" no gases would be needed to add additionalheat to the hot fibers; emerging from the bushing.

Referring more particularly to F l of the drawings, refere c a ac r;epresents tutnacevin which a supply bodyfz of Quiche i .t1eta'1;-v

r al is c ntained. Oust-lief .loweraside-or theflfurn i orifi es'throughwhich the; refractory-"fi ers e; drawn. Ihebushing 3, vzfcan be-;heated by; an electric heating. element to "keep. theimo1tenrefractory. material t atta'ny desired tem ratureiie Afterleaving the bushing;

' enter a gas chamber 5fwhich maycontain either inert,-

non-oxidizing or reducing gases; A's aforementioned, these gases may beused to control theltemperaturettot the fibers, to obtainthetdesiredfinal physical properties,

' and to, lp'repareihe'fibers"forl'subsequent.coatings; If

Qn e or more coatings of metal and/or inorganic mat-,1

terials, or an inorganic material followed by an organic material, maybe appliedto thetrefractqryg fibers, if desired, before they are bondedtogether. "In such cases,

i V ist fi i 11 u ee szoi;therrefractory,fibers can be ,7

pr tected frgm any harmfulatmosphere'by;surrounding ingandiornon-oxidizing gas by a y suitablemean'ssueh 55: 23'". qi l l t tiug,jsuch gas ,through chamber means 1 fibersbetween coatingswith'eitherjan inert, .reduc i the coating apparatus' 'is tlocatediin:1he immediatevi'cinity of the bushing,- or relatively close, thereto, -no g'asesmaybe necessary and the. gas chamber s 'maybe' omitted;

The refractory fibers 4*. pass "through the gas chamber 5 into a tank;in which there". isfia suitable electrolytic bath' J1. ",Thegcathode is"designated as-8 andcomprises a 'se'riesbf power-driven;

iderrolls. 'Ihese-ArOIIs -can be constriictedas shown by FigQ'7 so thatonly that of the; surface of the;roll whichjcontacts tlie 'fibers is conthrgu'gh which thefibersfare .pas'sed. As, explained; above, this gasmay'alsobe'heated, if desired, to maintain'jthe. fibersat any desiredtemperature. t

esainiunieoppe'r, antimony, bismuth and alloys thereof.

l'he bonding material canal so be an inorganic material as; a"phosphate, a metal. phosphate, a metallo-silica e, temperature organicmaterial, ,such' as a polyester resin, a phenolic resin, a fluoro-ethylenecompound, 'a triallyl c'yanurate; a methyl methacrylate; asilicone or epoxy.

'Instead of'usi'ng' a bonding material, the-coated re fractory fiberscan bebonded togetherto form a lam i hate by'th eapplication of heatalone, or by heat' and pressure. The bonding material can be'applied tothev coated lhemo st su table honding materialsvfor applicationfon'; (Hecoated rejr'raetory; fiberslto forma la'minate are t low melting pointmetals or eutectic-of such metals, such as lead, tin, aluminum,magnesium-indium,

ajcomp'le'x' titanate, a 'borate, et' cetera, or a high ductive; 1 TAmore 1 detailed} descriptionbf theserolls' is included infra. An'o'des'2 are} provided in thektank 6, and, as illustrated, the ttankj6 is madewith/two chanti hers o aridQII "s'eparat edby; a} plate: '125'whichextends downwardly from 'thegas chamber 5 nearly e'='he;1ewer guide roll8 Power-drivendensiiiiij rolls 14ar'e pro: videdflto E'pull ;therefractory fibersfthrough the furnace bushing and-thenthroughtheg'as'and eleetrolyt'e' cham bers; iThe" tension rolls 'I4 :a'nd theguide rolls -8 andi8f are electrically'synchronized' to prevideieonstanes eed; 7

' and tension onthe fibers as they proceed" through are refra'eto'ryfibe'rs toform .a laminate lay-processes utiliz ing spraying, brushing,metallizing, electroplatingfhot molten baths, .Jet'cetera; Theseprocesses for applying the bonding materiallarexwell known-andthe choicedepends upon the particular bonding material used and/or the de iredstructural shape of the laminate; V

V advantages Qfithis invention will be readily appreciated. as-thepsame1 Othetjobjects and many of the attendant becomes better understood-byreference :to;the follow:

ing detailed description when considered in connection 'Wl h'l n f s h rin: 7

1g. ,1 is a perspectiv iew of an emb'odiment'of, the

firesentifinvention, showing in section an electrolytic nie anslforcoating the refractory fibers. I

, spray means "'18,

laminate in the form or a cylindertcanjbejformed asthestrandis wound'o'n the -reel 17,'by}spra'ying the desired bonding material onto saidstrand by any-suitable If it is desired to form theglaininate seawee -ten the strand m ygee auewea wiae iminate on the reel .17 to any'desiredthiclinessalndat -that the ftubular accumulation can be removedandfabricated elsewhere into a laminate. r

x As. an alternative to' the cylindricaltcolle'cting reel 17 a reel jof'any other jdesired crossisectional zshapezcaneb used to form alaminate"with -a correspondigg;shape,;T

molten bath means for 3, -t-lie ,refractory 'fibersp l I Laminates ofvarious shapes can also be formed by cutting the accumulated refractoryfiber mat ofi reel 17 along line 19 after it has been bonded by spray18, and then employing a heated press and die to shape the laminate. Theuse of a heated press and die for such purposes is well-known in thelaminating art.

Fig. 2 is illustrative of another continuously operating apparatus forcarrying out my invention and shows how a plurality of coating units,generally designated by reference numeral 20, may be utilized in formingthe laminate. In the embodiment illustrated, three coating units, A, B,and C, are utilized, however, it is obvious that a greater or lessernumber of coating units may be used. These coating units can be of thetype shown in either Figs. 1, 3, 4, 5, or 6. After the refractory fibersare coated with the desired coating material they are deposited on aconveyor 21 at the points shown as 22, 23 and 24. The conveyor 21 thenmoves the coated refractory fibers under spray heads 25, 26 and 27 whichspray the bonding material onto the fibers, at the desired temperaturesand in the desired amounts. These spray heads may be in the form ofelectric guns which deposit molten material upon the fibers to bond themtogether. A plurality of such guns can be arranged to deposit whateveramount of bonding material is desired per unit of time. The speed of theconveyor 21 may also be coordinated with the fibers as they aredeposited on said conveyor, to produce a laminate in which the fibersare either unidirectional or undulatory in form. I,

The conveyor 21 carries the bonded fibers under a heater 28 whichsoftens the bonding material so that it may be rolled or compressed to aselected thickness by means of rollers 29 and 30. Additional heaters 31and 32. may be used to aid in the plasticizing or softening of thebonding material for the rolling step.

A reciprocating knife 33 can be utilized to. cut the laminate producedby the method heretofore described into predetermined lengths. Aplatform 34 is situated adjacent the reciprocating knife to catch thesevered pieces and to provide a place to gather such pieces in stackspreparatory to shipping them to the point of use or further processing,whichever is desired.

Fig. 3 is illustrative of an electrostatic spray apparatus for carryingout the coating step in my invention. A conventional refractory furnace35 feeds a plurality of refractory fibers 36 through orifices in abushing 37. A set of power-driven tension rolls 38 draws the fibersthrough the bushing 37 and into a chamber 39 containing either inert,reducing and/or non-oxidizing gases. The function of these gases hasbeen explained supra. An electrical heater 40 may be used Within the gaschamber 39 to aid in controlling the temperature of the glass fibers.

In using this spray apparatus a metal-bearing refractory mixture is notneeded. A member 41 is provided to contact the fibers as they passthrough the gas chamber to impart a charge on the fibers. This member 41maybe made of either a soft metal or carbon, and can be anchored by aspring 42 to allow this member to continuously contact the fibers.

After leaving the gas chamber 39 the refractory fibers pass into aspraying chamber 43 wherein the desired coafing material is applied atthe desired temperature by means of spray apparatus 44. A chargeopposite to that on the fibers can be applied to the coating material byany conventional means. Any unused coating material is drained ofi bychannel 45 which deposits such unused coating material in the supplytank 46. A pump 47 is provided to deliver the coating material to thespray apparatus 44. A set of squeegee rolls 48 is provided to removeexcess coating material from the con tinuously moving refractory fibers.In case the squeegee rolls 48 fail to remove all the excess coatingmaterial from the fibers, a wiper device 49 can be provided to assist inthis operation.

After passing through the Wiper device 49 and the tension rolls 38, thecoated refractory fibers are run through a guide member 50 and collectedinto a strand. The strand of coated fibers is then wound onto areciprocating and rotating reel 51. The tension rolls 38 and an idlerroll 52 can be electrically timed to provide the proper tension in therefractory fibers to prevent breakage during the coating process.

In this apparatus, as a result of the oppositely charged fibers andparticles of spray, the particles of the spray are attracted to thefibers and the latter are completely and uniformly coated.

Fig. 4 is illustrative of an electroplating apparatus for carrying outthe coating step in the invention. This apparatus comprises a furnace53, a bushing 54, an electric heater 55, and a gas chamber 56 attachedto the furnace. The gas chamber 56 and heater 55 func tion as explainedsupra. After leaving the gas chamber 56 the refractory fibers passthrough a fused salt bath chamber 57 containing anodes 58 of the desiredcoating material. When using this apparatus a metal-bearing refractorymixture will have to be used to provide a fiber that is conductive. If anon-metal-bearing refractory material is used, a pre-coating conductivefilm will have to be applied to the furnace of the fibers before thefibers enter the plating bath. The charge on the fibers is impressed bymeans of the power-driven idler rolls 59. An exit gas chamber 60 isprovided for quenching and/or oxidization control purposes. Themechanical drawing power for the fibers is provided by tension rolls 61.From the tension rolls 61, the fibers pass through a conventional guidemember 62, by an idler roll 63 and thence onto a reciprocating androtating reel 64.

Fig.5 is illustrative of a dipping or molten bath apparatus for carryingout the coating step in the invention. From the conventional refractoryfurnace 65 and bushing 66 the refractory fibers pass successivelythrough a gas chamber 67 having a heater 68, a bath chamber 69, aquenching gas chamber 70 and thence through a guide member 71 onto areciprocating and rotating reel 72. The fibers are drawn through theapparatus by tension rolls 73 assisted by power driven guide rolls 74,75 and 76. These rolls are electrically synchronized to maintain theproper tension in the fibers to prevent breakage. The coating materialis indicated by reference numeral 77. The use ofsuch a molten bath forplating purposes is well-known.

Fig. 6 is illustrative of a vapor deposition apparatus for carrying outthe coating step of the invention. Again the conventional refractoryfurnace 78, bushing 79, heater element 87, and gas chamber are employed.After the refractory fibers leave the gas chamber 80, they enter a vapordeposition chamber 81 containing a metal vapor at an elevatedtemperature. The metal is deposited upon the moving heated refractoryfibers (or substrate), the fibers acting as a condenser. The temperatureof the vapors and the pressure in the deposition chamber 81 may becontrolled as desired to obtain optimum coating conditions. From thedeposition chamber 81 the coated fibers pass through a reducing gaschamber 82, where the desired temperature is maintained, through tensionrolls 83, a guide member 84, idler roller 85, and then ontoreciprocating and rotating reel 86.

The same apparatus as shown for a vapor deposition process for coatingthe refractory fibers could also be used for applying the coatingmaterial by a gas plating process with one exception, a heater wouldhave to be provided to heat the substrate in the deposition chamber.This process is carried out by heating the substrate in an atmosphere ofa metallic compound, such as a metal-carbonyl, or a metal hydride or anequivalent. Since the metallic compounds used are more volatile than thefree metals, the temperatures required for evaporationare Ym'uch lower.It is 'advantageous'in some instances when usinglthisamethcd tOl-Bddinert or' reducin'g or non-oxidiziiige'gascs itol the tcarbonyl orhydride vapors during zthe platingiprocesssince' they act as a'icatalystand ;hasten.the

metallicfleposition process.

7 In the use of any of the apparatusdescrilredzin the preceding figuresfurnace. Factors to' be considered :whenipositioning the coating deviceare the speed of thefibersfiand theetem- 'perat-ure diiierentialsthatmust be maintained between V thefibers'an'd' the coating material. 7 V jpreviously mentioned, the refractory 'rfibers' gin-the 'apparatusofjFigureslthr ugh 6 are drawn' throughithe coating device-in=each"in'stance by 'meansof a setofiten- "sion "rolls 'aided by aplurality 'offpower-"driv'en .irolls.

' These tens ean be 's ynchronized by{an"electrica1 control device to'provide a constantspeed" as thejfibe'rs fpass .throughfthe-coatiugapparatus. 1 'l'he recipr'ocatingpwinding .or collecting reel in eachcase acts 'as' a reeling a'pparatus' only, not"for drawing the fibersthrough 'the' coatin'g apparatus.

V Fig. 7"is illustrative ot-;a's et'of povver driven tension 25 *rol1s88; such as are used' in the 1 apparatus of Figures l thircuigl1"6.'J'Each roll can have a-plurality' of grooves 89, 90 initsouter 'surfaceat the'points where thefibers are'contaeted All of the'sin'gleguide'rolls shovy'ndn Figures lithrough: 6 may be made withj'similargrooves. 30

'When'using the'coatingprocessof Figures 1 m3, the center of the'guide.and tension 'rolls 92 and the aforementioned grooves '89 and 90, shouldbemade'of-a conductive metal, while the other parts 91 of the rollersshould be made'of' a non-conductive material to" prevent theaccumulation of coating'materials on 'these rolls. In the'claimsthe"term"meta:llic materialfds intended to mean either, ametal oran'alloy. f'The term"inor- ,"g anic substance as used intheclaims is'intended'tomclude elemental metals, alloys andinorga'nic c'ompounds.

The Word ,plir refractory fibersas used theclaims is intended tomeanthatprior'to'coating', the surfaces of thefibers 'ar'e susbtantiallyfree from harmful or foreign films, such as organic films, andoxidized-films caused by exposure to atmospheric conditions'for an unduelength Qdftime; andother impurities. Asfexplainedjabove'the fibers are"protected against'the formation of'such films,

' bysurroundingthem with inert gases, etic'ete'ra; or: by

applying the. alien. coating in relatively close proximity .to Ithebushing before the "fibers have a chance to be 1 duly exposed to anyharmful atmosphere,"whereby"the 'fibersar e retained substantially: inthe "purestate.

In Figures 1 through 6 only one'coating is'ishown being -applied but aspreviously mentioned it is contemplated that-a plurality ;of coatings?ay be applied before'the bonding op'erationisperformed. ."Ihe pluralityofcoat- -.in gs rnay comprise any ,of the. above, disclosed metallic:and/or inorganic materials, or they may 'comprise any of theseinorganic materialsfollowed by an organic'matezrialselected from thegroup of organic bonding materials --disclosed above. In order to applya pluralityof coatings, it is merely necessary to pass the fibersthrough additional coating units in series. If the coating unitsofj-theseries are spaced relatively far apart, it will be desirabletosurround the fibers as they pass between units withan' inert, reducing,and/ or non-oxidizing gas. This may. be. accompli'shed by means of-achamber through which the fibers j are-passed and gas supply meanssuch-as} previously .described. a i' i Obviously many modifications [andvariations of the present invention are possible in the light roftheabove It is' therefore to be understood: that. within teachings. V V Vthe scope of the appended claims 'thexinventionzmayrybepracticedothenwise than as specifically describd,

:The usetof a gasplating or V a disasso'clation of metal .processvforvplating is wellknown in thplating' art.

l throu'gh 6, the coating'xievice may be 'placed at anydesirabledistance from 'the refractory ;I claim: 7 a i r 7 f -2A een inou methqd rip oducin a tes e 7 .3 tory fiber-comprising the stepsof'drawing ag cgnfinuous fib r; hroug 5: 1 ush g f m a nQ a eefin 5refractory material, continuously. drawing; successive -adjacent'portions of saidffiber 'through'an electrolytic ;bath

1 While asaid fiber is still in thepure condition existent at thetimeitemerged'frcm the bushing and electrodepositing a'metal coatingthereon.

10 =2..A,"continuous method :for. producing a -coated refractory fibercomprising: the steps ,oi forming a-.c ontinu ousafiber from amolten-metal bearingvrefractory material, Y continuously drawingsuccessive "adjacent portions ofisaidi'fiberpwhile still in the ;purecondition existent at the timefg ofjformation through a.heated-pure,idrynonoiiidizi-ngggas anklithen through an.:electrolytic ;-bath,=:andelectrodepositing ametalccoatington said-:successivezportionsfrom saidhath.

: 3. -'A continuous :lmetho'd .for producing :a ;coated:.re'-

fractory fiber as set iot-thin :claim .1 iniwhichitheisaid port 'ns ofsaid fibers, while-still in the pure con'dition {existent-at the timejo'f formation through an electrolytic bath forelectrodeposition ofa'coating material e the surface of each, '-and'-collecting';said-fibers into-a' continuous strand. 7

. f6. A "continuous method for producing an article'of coated refractoryfibers comprising the'steps of drawing continuous,'moying, pure fibersfrom a molten metal bearjirigTjeft'actory "material, successivelydrawing successive 'a'djacenfportions iof said fibers, While still in ethe pure condition existentat the time of"formation through anelectrolytic bathfortelectrodeposition of a coating mate- ;rial ion" thesurface "OfTaCh, "collecting said ffibers into a continuous strand;and'collecting said strand int o a cylina 'dricatform; 7 a V :7. Acontinuous'jmethodforproducing an:article-of coatedrefractoryfibers/comprising the stepsof drawing continuous,moving,1purefibers:from"a molten'metal' bear- 'ing refractory material,successively drawingsuccessive adjacent; portions (ifsaid i fiberswhile." still in {the pure condition existent at the time of formationthrough "an electrolytic bath. for electrodepositionof a coatingmaterial onithe surface of each, zcollectingsaidf fibers into acontinuous .strand; collecting said strand ginto layers, fspraying'thestrand portions bjeingccllected withfa bonding materialto .effect anintegralmelationshipthereof, heatings'aid bonded strand portions tosoften'the bonding material and then pressure shaping said layers otstrand 0 to desired; form. a

8. "A method for producing a coated refractory fiber 7 compris ng thesteps-ofrforminga continuousfiber of :said refractory-material from amolten bath of said reifractoryztmaterial'and a reducible metal oxide,continuously reacting successive; adjacent portions .of said -fiber withahot Edryzpure reducing igas while said tfiber isin -the pureconditionexistenti at-the time of its formati0n Whereb'yto reduce-said .m'etaloxides at-the surface-Lot said refractory fiber 'to abasemetal film,andthen elec- 'tro'depositing a: seconddayer of a metaloversthetsur-face' 1 et-the, base metalifilma on said retractory fibercondition 'as'obtained fromithe reducing step. 7

(References on f ollovdngfipagef I References Cited in the file of thispatent UNITED STATES PATENTS Hoyt July 28, 1925 Bennett Dec. 2, 1941 6Hood Jan. 25, 1944 Goebel et a1 Mar. '13, 1951 Modigliani Mar. 27, 1951Brennan Dec. 18, 1951 Smith Apr. 29, 1952 10 Brennan Nov. 4, 1952Simkins et a1 July 7, 1953 Nachtman Ian. 11, 1955 FOREIGN PATENTS 7'France Dec. 2, 1939 OTHER REFERENCES The Glass Industry on January1947, pp. 43 and 44.

1. A CONTINUOUS METHOD FOR PRODUCING A COATED REFRACTORY FIBERCOMPRISING THE STEPS OF DRAWING A CONTINUOUS FIBER THROUGH A BUSHINGFROM A MOLTEN METAL BEARING REFRACTORY MATERIAL, CONTINUOUSLY DRAWINGSUCCESSIVE ADJACENT PORTIONS OF SAID FIBER THROUGH AN ELECTROLYTIC BATHWHILE SAID FIBER IS STILL IN THE PURE CONDITION EXISTENT AT THE TIME ITEMERGED FROM THE BUSHING AND ELECTRODEPOSITING A METAL COATING THEREON.